<!DOCTYPE html>
<html lang="zh-cn">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Title</title>
    <link rel="stylesheet" href="./css/base.css">
    <link rel="stylesheet" href="./css/13.css">
</head>
<body>
    <div class="box1">盒子模型</div>
    <hr>
    <div class="box2">盒子模型</div>
    <hr>
    <div class="box3">盒子模型</div>
    <hr>
    <span class="nav">元素1</span><span class="nav">元素2</span>
    <hr>
    a
    <span class="box4">元素内容</span>
    b

    <br><br>
    a
    <img class="img-box" src="../assets/img/loading.jpg" alt="" srcset="">
    b
    <audio src="../assets/media/sample-3s.mp3" controls style="width: 400px"></audio>
    <hr>
    <div class="box5">
        <span>内间距<br>的设置</span>
    </div>
    <br><br>
    <div class="item">内容内容内容内容内容内容内容</div>
    <hr>
    <div class="m-box-1">
        <div class="c-box-1">内容内容内容内容内容内容内容</div>
    </div>
    <hr>
    <div class="m-box-2">
        <div class="c-box-2">内容内容内容内容内容内容内容</div>
    </div>
    <hr>
    <div class="m-box-3">
        <span class="c-box-3">内容内容内容内容内容内容内容</span>
    </div>
    <hr>
    <div class="m-box-4">
        <div class="c-box-4">内容内容内容内容内容内容内容</div>
    </div>
    <hr>
    <div class="item-1">aaaaaaaaaaaaaaaaaaaaa</div>
    <div class="item-2">bbbbbbbbbbbbbbbbbbbbbbb</div>
    <hr>
    <div class="border-box">边框</div>
    <hr>
    <div class="border-triangle"></div>
    <hr>
    <div class="border-radius">直角</div>
    <div class="border-radius border-radius-1">圆角</div>
    <div class="border-radius border-radius-2">圆角</div>
    <div class="border-radius border-radius-3">圆角</div>
    <div class="border-radius border-radius-4">圆角</div>
    <div class="border-radius border-radius-5">圆角</div>
    <div class="border-radius border-radius-6">圆角</div>
    <div class="border-radius border-radius-7">圆角</div>
    <hr>
    <div class="border-img"></div>
</body>
</html>